Senior Systems Engineer – Mechanical

Fleet Data Centers – Position Overview

Fleet Data Centers designs, builds and operates mega‑scale data center campuses, providing customers with flexibility and predictability to meet their upside demand forecasts. Fleet is led by industry veterans committed to uplifting data center development scale and operations in the face of rising demand. Fleet is headquartered in Denver, Colorado, with satellite offices in Seattle, WA and Arlington, VA.

We are seeking a Senior Systems Engineer – Mechanical to own the detailed design validation, analysis, and ongoing optimization of Fleet’s data center cooling topology from campus level through the rack. This role requires a deep understanding of Fleet data center cooling topology, including air‑side and liquid‑side systems (fan walls, CRAHs/CRACs, chillers, dry coolers, pumps, heat exchangers, distribution manifolds, in‑rack cooling components) and how these components interact under a variety of operating and failure scenarios.

The ideal candidate will pair strong mechanical engineering fundamentals with practical data center cooling experience, ensuring that the air‑to‑liquid mix and cooling configuration for each deployment match rack layouts and rack SKUs, that CFD and failure‑mode simulations are routinely used to de‑risk deployments, and that cooling system behavior is well understood and systematically improved.

This role is accountable for end‑to‑end thermal system integrity, including aisle‑level optimization, fan wall octet configuration, failure‑mode simulations (e.g., CRAC outage, dry cooler outage), and impact assessment for infrastructure upgrades and expansions, with the goal of optimizing uptime SLAs and minimizing cooling stranding.

We have a hybrid policy, and candidates can sit in Seattle, WA, Denver, CO, Austin, TX, or Alexandria, VA.

Cooling Topology Ownership & Rack‑Level Alignment

• Develop and maintain a deep understanding of Fleet data center cooling topology, including air‑side systems: fan walls, CRAHs/CRACs, air handlers, ducting, containment, filters; liquid‑side systems: chillers, dry coolers, pumps, CDUs, heat exchangers, headers/manifolds, valve trains; rack‑level solutions: liquid‑cooled cold plates, rear‑door heat exchangers, in‑rack manifolds, hybrid air/liquid configurations.
• Determine the air‑to‑liquid mix needed to support a given rack layout and density, considering rack SKUs, aisle configuration, containment, and site constraints.
• Ensure cooling topology and capacity at room/aisle level support current and forecast rack deployments and density targets.

Rack SKUs, Cooling Requirements & Data Accuracy

• Understand the air and liquid cooling requirements for each rack SKU, including inlet temperature and humidity ranges; liquid flow, pressure, and temperature ranges for cold plates and rear‑door heat exchangers.
• Maintain structured mapping from rack SKUs to required airflow per rack/aisle, required liquid flow per rack/manifold/loop, and special constraints (e.g., mixed air/liquid aisles, max ΔT).
• Ensure specifications and counts for cooling components (fan wall modules, CRAHs/CRACs, CDUs, pumps, valves, manifolds, piping sizes, coils) are accurate, documented, and provided to capacity planning and procurement.

CFD & Thermal Analysis

• Perform CFD analysis at room and aisle level to validate rack placement, confirm airflow patterns, pressure profiles, and temperature distributions, and identify and mitigate cooling stranding.
• Use CFD and thermal modeling tools to evaluate rack arrangements, containment strategies, test sensitivity to IT load changes, fan speeds, supply temperatures, and air‑to‑liquid mix, quantify margins to thresholds (e.g., maximum rack inlet temperature, component temperatures).
• Translate CFD results actionable design rules, placement constraints, and deployment guidelines for capacity planners and operations.

Aisle‑Level Optimization & Fan Wall Configuration

• Optimize cooling for each aisle based on IT load distribution, air‑to‑liquid split, and containment strategy (cold aisle, hot aisle, full containment, partial containment).
• Recommend fan wall octet configurations per deployment…